Sensory Mechanisms Limiting Connectivity At Different Scales
Jelle ATEMA*1, Gabriele GERLACH2, Vanessa MILLER-SIMS3,
Biology, Boston University, Boston, MA, 2University of Oldenburg,
Oldenburg, Germany, 3University of Southern California, Los Angeles,
CA, 4James Cook University, Townsville, Australia
International Coral Reef Symposium
Fort Lauderdale FL. July 2008
Mini-symposium Reef Connectivity (#14)
Jelle Atema, Gabriele Gerlach, Vanessa Miller-Sims, Michael
Presenter: Jelle Atema, Boston University
Sensory mechanisms limiting connectivity at different scales
Evidence from different coral reef fish species shows that settling larvae
prefer the odor of the reef where they were captured. Indirect evidence
shows that this is most likely also their natal reef, where odor imprinting
occurred at hatching as demonstrated in Amphiprion sp. imprinting on
anemones. When settling, different species appear to use this odor
information differently resulting in different connectivity scales.
The cardinal fish O. doederleini shows limited larval dispersal and
strong homing. Genetic data show that it does not often survive to
maturity in non-natal reefs even as close as a few km away. Behavioral
experiments show that settlers from foreign reefs face severe conspecific
competition, reflecting perhaps a limitation on settlement sites. Such
post settlement competition would exert strong selection pressure for
homing. In habituation tests they show persistent home odor preference.
Other cardinal fishes behave similarly in odor choice tests. In contrast,
the damsel fish P. coelestis can settle “abroad” and genetics shows it
does so at a spatial scale of 20-100 km. This relaxes selection pressure
for homing and facilitates the wider dispersal. Settlers still show
evidence for imprinting on reef odor but their odor preference is less
persistent. They may use their knowledge of home odor to later
recognize any reef. This species settles on outer reef slopes where
competition for settlement sites may be less severe. Finally, the damsel
fish A. polyacanthus guards its larvae, which do not have a pelagic
dispersal phase and do not show home odor preference in choice tests.
Their behavior appears to allow for juvenile integration into adult habitat
with very limited local dispersal.
In ocean environments it is important to understand the local
hydrography and the spatial-temporal scale of mixing water masses,
identifiable by the odor of their origin.